A firefighter can search 100 Sq ft in 10 seconds, how many firefighters are needed to search 5000 Sq ft in less than 2 minutes

Question

Not looking for an answer. More how to set this problem up to be solved. 

Answer 1

1 firefighter can search 100 sq ft in 10 seconds is the starting point.

First I would calculate up to 5000 sq ft as follows: (5000/100) x 1 firefighter = 50 firefighters

 

So 50 firefighters can search 5000 sq ft in 10 seconds.

 

If time is increased to 2 minutes (120 seconds), we don't need as many firefighters. We can reduce the number by the ratio 10 seconds / 120 seconds.

 

(10/120)*50 = 50/12 = 4.17 firefighters

 

So we need a minimum of 5 firefighters to be under 2 minutes.

Answer 2

First, we need the same units. 2 minutes = 120 seconds so one fireman can search 100/10 = x/120 square feet which is 1200 square feet in 2 minutes. 

1/1200 = x/5000  the number of firemen needed/sq ft they can search. Solving, x= 4.166666666.

Rounding off is not always appropriate. 4 firemen could not complete this task. 4 firemen could cover 4800 square feet. So we need 5 firemen.

Answer 3

Mauricio,

 

Since you are given how the number of square feet a single firefighter can search in 10 seconds it's easy to calculate the number of square feet he can search in 1 minute (6 x 10 sec) and then in 2 minutes.

 

Then 5000 sq ft divided by the number of square feet a single firefighter can search in 2 minutes will tell you how many firefighters are needed